Engine manufacturers typically run their engines through a “break in” phase to provide initial lubrication and wear to various parts of the engine. For example, in the context of a propeller engine for an aircraft, an engine break in station typically resides at the end of the manufacturing line. At the break in station, the manufacturer typically fastens a newly built engine to a stationary footing or foundation, installs a load (e.g., a propeller) onto the engine's drive shaft, and connects fluid and electrical lines to the appropriate engine locations. The manufacturer then runs the engine for a period of time (e.g., one or two hours) at various speeds (i.e., different RPMs). During this time, the manufacturer typically monitors various operating parameters of the engine such as oil temperature and pressure to confirm that the engine is operating properly.
Some engine manufacturers occasionally pull engines from the end of their manufacturing lines and put these engines through extra tests. For example, in the above-described context of a propeller engine for an aircraft, a manufacturer may measure engine horsepower from a sample of engines after the break in phase in order to obtain confidence that all engines coming off the manufacturing line are capable of providing a certain specified horsepower. To this end, the engine manufacture typically removes a sample engine (e.g., one out every ten engines) from the break in station and transports that engine to a dynamometer station. The manufacturer then connects the sample engine to a dynamometer.
In one conventional dynamometer setting, the engine manufacturer connects the drive shaft of the sampled engine to an electric generator which operates as the load. The manufacturer then runs the engine at various speeds and obtains an electric output signal from the electric generator. The manufacturer converts that signal into horsepower measurements. In other conventional settings, a load other than an electrical generator is suitable as a load/power absorber (e.g., a water brake, a compressor, a fan brake and a pony brake).